<?php

/**
 * Zend Framework
 * LICENSE
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 * @category Zend
 * @package Zend_Paginator
 * @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
 * @license http://framework.zend.com/license/new-bsd New BSD License
 * @version $Id: SerializableLimitIterator.php 24593 2012-01-05 20:35:02Z matthew $
 */
/**
 *
 * @category Zend
 * @package Zend_Paginator
 * @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
 * @license http://framework.zend.com/license/new-bsd New BSD License
 */
class Zend_Paginator_SerializableLimitIterator extends LimitIterator implements Serializable, ArrayAccess {

    /**
     * Offset to first element
     * @var int
     */
    private $_offset;

    /**
     * Maximum number of elements to show or -1 for all
     * @var int
     */
    private $_count;

    /**
     * Construct a Zend_Paginator_SerializableLimitIterator
     * @param Iterator $it Iterator to limit (must be serializable by un-/serialize)
     * @param int $offset Offset to first element
     * @param int $count Maximum number of elements to show or -1 for all
     * @see LimitIterator::__construct
     */
    public function __construct (Iterator $it, $offset = 0, $count = -1) {
        parent::__construct ($it, $offset, $count);
        $this -> _offset = $offset;
        $this -> _count = $count;
    }

    /**
     *
     * @return string representation of the instance
     */
    public function serialize () {
        return serialize (array('it' => $this -> getInnerIterator (), 'offset' => $this -> _offset, 'count' => $this -> _count, 'pos' => $this -> getPosition ()));
    }

    /**
     *
     * @param string $data representation of the instance
     */
    public function unserialize ($data) {
        $dataArr = unserialize ($data);
        $this -> __construct ($dataArr['it'], $dataArr['offset'], $dataArr['count']);
        $this -> seek ($dataArr['pos'] + $dataArr['offset']);
    }

    /**
     * Returns value of the Iterator
     * @param int $offset
     * @return mixed
     */
    public function offsetGet ($offset) {
        $currentOffset = $this -> key ();
        $this -> seek ($offset);
        $current = $this -> current ();
        $this -> seek ($currentOffset);
        return $current;
    }

    /**
     * Does nothing
     * Required by the ArrayAccess implementation
     * @param int $offset
     * @param mixed $value
     */
    public function offsetSet ($offset, $value) {}

    /**
     * Determine if a value of Iterator is set and is not NULL
     * @param int $offset
     */
    public function offsetExists ($offset) {
        if ($offset > 0 && $offset < $this -> _count) {
            try {
                $currentOffset = $this -> key ();
                $this -> seek ($offset);
                $current = $this -> current ();
                $this -> seek ($currentOffset);
                return null !== $current;
            } catch (OutOfBoundsException $e) {
                // reset position in case of exception is assigned null
                $this -> rewind ();
                $this -> seek ($currentOffset);
                return false;
            }
        }
        return false;
    }

    /**
     * Does nothing
     * Required by the ArrayAccess implementation
     * @param int $offset
     */
    public function offsetUnset ($offset) {}

}
